Disposable face masks or respirators have previously been made by combining a layer of fibrous filtration media with a preformed fibrous shell. The latter establishes and maintains the shape of the face mask; the filtration media conforms to the shell and is supported and protected by it.
The combination of a filtration layer with a preformed shell, whether done manually or by machine, is time consuming and adds complication to the manufacturing operation. In addition, the filtration layer is sometimes creased, stretched, or folded during the assembly operation, which typically causes deterioration of the filtration properties of the layer.